997 c2s engine rebuild 6th gear ratio and flywheel mods

[Rossco196x]

Hi Folks after much pondering i've decided to get the ill sounding engine (tapping like a stuck follower) out of my 997 c2s and strip it down ready for a bottom end rebuild which i will have performed by a reputable 997 specialist and basically i'm probably going to send the bottom end (heads removed) for re sleeving and new shells etc. so a couple of questions.

1, I think this engine has the earlier small IMS bearing (2004 MY) that is serviceable in situ and hence i was intending to replace the bearing only rather than modify as i'm intending to increase oil change frequency to every 5k. Is this advisable as i think the IMS bearing is probably not so much of an issue and could be changed every time the the clutch is done circa 40k.

2. Is it worth changing the flywheel to a lighter item, this made a very big difference to my 964, and if so what is the cost.

3. What other mods are worth considering as in i don't have an unlimited supply of cash but if there is a chance to gain a few extra useable BHP. I have already changed the exhaust manifolds.

4. I'd like to change the 6th gear ration to reduce revs for motorway cruising and perhaps a few extra MPG as i rarely see 22 MPG. Has any one done this as the box will be out.

I will also overhaul the heads and replace the chains as a precaution. On a sader note i feel ripped off by Porsche as this engine was clearly poorly developed resulting in a need to rebuild at 63k miles.

I did consider selling the car but was barely able to get an offer of £16k so the £7k cost of rebuilding will be offset over the next 10 years of ownership.

Thanks